In a general building, there are many places where heat is taken in and out through a window portion. Specifically, when air cooling is performed during summer, heat is taken from the outside of the building into the inside of the building so as to increase indoor temperature, and when air heating is performed during winter, heat is discharged from the inside of the building to the outside of the building so as to lower indoor temperature. That is, a large amount of energy is lost through the window of the building, which reduces the cooling and heating efficiency.
Further, since light is transmitted through the window of the building, it is possible to view the outside from the inside of the building, or it is possible to view the inside from the outside of the building. Here, in a window of a bathroom in the general building, it is desired that, during use of the bathroom, the bathroom is prevented from being viewed from the outside of the building. Therefore, the window is provided with a blinder plate which is made of an acrylic plate or the like and is referred to as a louver. However, in such a case where the bathroom is not used, it is preferred that light is taken into the bathroom through the window. Therefore, it is necessary that the amount of light taken into the bathroom is changed by adjusting the amount of opening of the louver according to the use state of the bathroom.
In order to solve the above-described problem in the window, research and development of dimming glass are conventionally performed. As the dimming glass, there are glass whose transmissivity is changed according to the amount of current or voltage supplied to the glass, glass whose transmissivity is changed according to temperature, and glass whose transmissivity is changed by controlling ambient gas. Among these types of glass, the glass whose transmissivity is changed by controlling ambient gas has been receiving particular attention from the viewpoint of the simplification of structure and the reduction of cost.
For example, as dimming glass whose transmissivity is changed by controlling ambient gas, a reflection type dimming thin film material, which can be colorless and transparent, is disclosed in Patent Document 1. In the dimming glass which is represented by Patent Document 1 and which is also referred to as gas chromic glass, the transmissivity is controlled by adjusting the amount of hydrogen inside of the glass in such a manner that hydrogen is introduced to the inside of the glass (hydrogenation), and further that the amount of the introduced hydrogen is reduced, such as by discharging the hydrogen (dehydrogenation).